Carrier manual Indoor Thermostat IT CONTACTS, ALL 52CQ, PQ Models

52C,P

SERIES

1	BLK
2
3	BLU
ORN
4	GRY
5
6	BRN

IT

FIGURE 49 — INDOOR THERMOSTAT (IT)

CONTACTS, ALL 52CQ, PQ MODELS

■OUTDOOR FROST THERMOSTAT (Heat Pump Units) (Figure 50A and 50B) — The Outdoor Frost Thermostat (OFT) is a thermostat that uses a single- pole switch with a manual override selector. The ther- mostat switches between electric heat and compressor operation when the temperature of the outdoor coil falls below 20 F or rises above 35 F. Switching the override selector to electric heat disables the reverse cycle operation of the thermostat and is manually switched to electric heat operation.

IMPORTANT: Placing the override switch to elec- tric heat mode operation will disable the compres- sor for ALL heating or cooling operations (for all units except RC units). Placing the override switch to electric heat mode operation on RC units will only disable the compressor in heating mode.

FIGURE 50A — OUTDOOR FROST THERMOSTAT (OFT) CONTACTS, ALL 52CQ, PQ UNITS WITH MOUNTED CONTROLS

FIGURE 50B — OUTDOOR FROST THERMOSTAT (OFT) CONTACTS, ALL 52CQ, PQ UNITS WITH WALL THERMOSTAT CONTROL

To verify the OFT is operational, a continuity test may be performed as follows:

1.Turn off unit power as described in UNIT DISASSEMBLY section.

2.Remove the leads from the OFT. Note their loca- tions to ease re-assembly.

3.Connect the continuity tester to the switch termi- nals marked 1 and 2.

4.Rotate the override switch to the electric heat set- ting and verify that there is continuity between terminals 1 and 2.

5.To check the other contacts, move the lead on ter- minal 1 to terminal 3. Rotate the override switch to the heat pump setting. There should now be continuity between terminals 2 and 3.

6.Once the test is complete, reconnect the leads.

■CAPACITOR — The 52C,P units use a dual capacitor. One part of the capacitor is used with the fan motor. The other part of the capacitor is used by the compressor.

Run circuits on single-phase compressor motors use capacitors which dramatically affect the motor opera- tion. Run capacitors are connected to the motor circuit at all times.

To evaluate the capacitor, perform a visual check first. A shorted capacitor may give a visual indication of its failure. For example, the pop-out hole at the top of a start capacitor may bulge or blow out. A run capacitor may bulge or leak. In these instances, the capacitor must be replaced with one recommended by the manu- facturer. If there are no visual signs of capacitor fail- ure, testing of the capacitor resistance may be done with a volt-ohmmeter as detailed below:

1.Turn off unit power as described in UNIT DISASSEMBLY section but do not unplug the service cord; it will supply ground connection for the unit chassis. Check to ensure power is off and LOCKED OUT.

2.Connect one lead of a 20,000 ohm, 2-watt resistor to the center group of terminals on the dual capac- itor. Attach the other lead from the resistor to an unpainted metal section of the unit chassis. This allows that section of the dual capacitor to dis- charge. Repeat this process between the other group of terminals.

Capacitors are capable of holding charge similar to a battery and may cause an electrical shock.

3.Locate and disconnect the wires from the start and/or run capacitor to isolate them from the remainder of the circuit. Refer to the unit wiring diagram if you need assistance locating wires.

4.Perform capacitor test. Set up the volt-ohmmeter to measure resistance by connecting terminals C to FAN and C to HERM on the meter. See Figure 51.

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